“The movement from low-level rules to higher-level sophistication is what we call emergence,” writes Johnson, explaining that local, parallel, cumulatively complex interactions result in some kind of discernable macrobehavior. And that behavior, if adaptive, has the distinctive quality of growing smarter over time. One needn’t be conscious or aware of the process, either, argues Johnson: if learning is considered the absorption and retrieval of information, then, for instance, the topography of a city qualifies as emergent behavior. An ant colony is another good example, where the ants as agents produce behavior that allows for a step in the direction of higher organization—from ants to colonies. Johnson’s clarity is a boon when it comes to explaining such ideas as swarm logic and the way phenomena like critical mass, ignorance, random encounters, pattern recognition, and local attentiveness result in a collective phenomena of remarkable elegance organized from below, without the dubious benefits of hierarchy. Emergence is nothing new, Johnson notes—surely the way in which the guilds organized themselves in 12th-century Florence is an example, let alone how the cells in our bodies act the way they do, for better or worse—but we are now simply recognizing it as a quiet, generative force working in theaters ranging from the slime mold (dissolving and regrouping upon signals from the molecular level) to the negative-positive feedback loops that self-govern sites on the Internet. Examples abound, and Johnson reaps them everywhere, from software design to CNN, where the common pool of news has allowed local networks to choose their own programming, subverting the mother network’s dominance.